Johnson attended Forman School for dyslexics[2] and University of Maine, where he majored in poultry husbandry, but did not graduate.[3] Johnson also served four years in the Navy during the Korean War.[2]

His early artistic efforts focused on painting, after which he turned to sculpture in 1968. Examples of his statues include:

The Awakening (1980), his largest and most dramatic work, a 70-foot (21 m) five-part statue that depicts a giant trying to free himself from underground. The sculpture was located at Hains Point in Washington, D.C. for nearly twenty-eight years while still owned by Johnson. It was moved to Prince George's County, Maryland in February 2008, and an attempt was made by the new curator to correct some of the scale distortions of the original installation by altering some implied underground connections and placing the parts in different relationships to each other.

Double Check (1982), a statue of a businessman checking his attaché case, formerly located in Liberty Plaza Park across an intersection from the World Trade Center, as part of the public space required by a zoning variance granted to the developer of the adjoining skyscraper. Widely published photographs of the debris-battered and dust-covered statue, were taken following the September 11 terrorist attacks in 2001. The statue, scars and all, was returned to a prominent corner of the restored and renamed Zuccotti Park in 2006, again open to the public. The statue has periodically been adorned by tourists, pranksters and even Occupy Wall Street protesters.

Hitchhiker (1983), a statue along the side of a road leading away from the campus of Hofstra University.

Competition (1984), A sculpture of Julie Wier, Fairview Heights, Illinois. Chosen to represent the spirit of the people of St. Louis as winner of the picture yourself as a work of art contest. Dedicated on June 16, 1984 unsigned St. Louis County Library in St. Louis, MO.

Copyright Infringement (1994), at Grounds for Sculpture, a facility founded by Johnson, is a sculpture named to flaunt his disdain for criticism of his copies of the iconic works of fine art artists with international recognition, representing the fine artist, Manet, whose work he has copied.

Unconditional Surrender (a series with several versions begun in 2005), a spokesperson for Johnson has stated that this series is based on a photograph that is in the public domain, Kissing the War Goodbye, by Victor Jorgensen,[6] however, the Jorgensen photographic image does not extend low enough to include the lower legs and shoes of the subjects, revealed in Alfred Eisenstaedt's famous photograph, V–J day in Times Square, that are represented identically in the statue. A spokesperson for Life has called it a copyright infringement of the latter image.[6] Nonetheless, the first version, a bronze statue of life-size, was placed on temporary exhibition during the 2005 anniversary of V-J Day at the Times Square Information Center near where the original photographs were taken in Manhattan.[7]

A proposal to establish a permanent location for a copy on the Sarasota bay front has generated a heated controversy about the suitability of the statue to the location, suitability as a military service memorial,[9] the permanent placement of any statue on that public property, as well as the particular issues of unoriginality, mechanical construction, and alleged kitschiness of the statue.[10][11] In final agreement documents, Johnson committed the purchase price to cover copyright liability damages in order to have the statue placed. The city was wary of accepting a gift that might result in a financial loss from a possible legal battle that evidenced merit, according to the city attorney.[12]

First Ride (2006), a statue of a father helping his young daughter learn to ride a bike, in Carmel, Indiana.[15]

Forever Marilyn (June 2011), a 26-foot (7.9 m), 17-ton representation of Marilyn Monroe standing over a gusty subway grate in her appearance in The Seven Year Itch. Until 2012, the sculpture was located at Pioneer Plaza in Chicago, where it attracted many visitors and some controversy.[16][17] It was moved to downtown Palm Springs, California in 2012 and in July 2013 P.S. Resorts announced that The Sculpture Foundation, owners of Forever Marilyn, would be moving it to New Jersey for a 2014 exhibit honoring Johnson at the 42-acre Grounds For Sculpture.[18]

For statues made recently in a series named, Iconic, by Johnson,[19] many of which are very large, a computer program is employed that translates two-dimensional images into statues that are constructed by a machine driven by the program. Often, these subjects are images that already are well known as the works of others, generating heated ethical controversies regarding copyright infringement and derivative works due to substantial similarity issues.

Johnson's work was labeled as "kitsch" in a 1984 article by an art professor and critic at Princeton University, who explained its rejection as he was commenting on a controversy raging about the work in New Haven, Connecticut.[20]

His 2003 show at the Corcoran Gallery of Art, "Beyond the Frame: Impressionism Revisited," which presented his statues imitating famous Impressionist paintings, was a success with audiences, but was panned by professional art critics of national stature and drew strong criticism[vague] from curators at other museums about a prominent museum of fine art presenting an exhibit of his work.[21][22]

Johnson is the chairman and CEO of The Atlantic Foundation, the foundation created by his father John Seward Johnson I in 1963. Johnson created the Johnson Atelier Technical Institute of Sculpture, an educational, nonprofit casting and fabrication facility in 1974 as a means of fostering young sculptors' talents, while creating a foundry designed to construct his statues that is so well-equipped and staffed that it is chosen by many renowned sculptors.[19] Educational programs at the Atelier ceased in 2004. The Johnson Atelier now operates as a division of The Sculpture Foundation and Johnson continues to realize his sculpture at the facility but casting is often performed off premisses with some of his larger works being cast in China.

He also founded an organization called The Sculpture Foundation, to promote his works. In 1987, he published Celebrating the Familiar: The Sculpture of J. Seward Johnson, Jr. (ISBN 0-912383-57-7)[19]

Under Johnson's direction, The Atlantic Foundation purchased the old New Jersey Fairgrounds in Hamilton, New Jersey and in 1992 founded the Grounds For Sculpture to display work completed at the Johnson Atelier and other outdoor exhibitions. In 2000 park operations were transferred to a new Public Charity with the same intent that continues to operate the park.[19]

Johnson also is the former president of a large oceanographic research institution in Florida founded by his father, the publisher of a science magazine, Johnson and his wife funded the construction of The Joyce and Seward Johnson Theater for the Theater for the New City, an Off-Broadway theater in New York.[19]

Johnson was excluded from his father's will, which left the bulk of his fortune to Barbara Piasecka Johnson, his father's wife and former chambermaid. He and his siblings sued on grounds that their father wasn't mentally competent at the time he signed the will. It was settled out of court, and the children were granted about 12% of the fortune.[23]

Johnson was formerly married to Barbara Kline. She often engaged in extramarital affairs in their home, driving Johnson to attempt suicide.[1][24][25] In 1965, he acknowledged paternity to Jenia Anne "Cookie" Johnson without a DNA test, to speed up the divorce process.[26][27] Years later, Johnson's family had a legal battle regarding Cookie Johnson's eligibility for a share in the Johnson & Johnson fortune. The court ruled in favor of Cookie.[28]

Johnson later married Joyce Horton, a novelist. They have two children: John Seward Johnson III and actress Clelia Constance Johnson who goes by the name India Blake.[2]